Method for photocatalytic dissolution of copper from electronic waste

Abstract

The application discloses a method for photocatalytically dissolving copper in electronic waste, and belongs to the technical field of photocatalysis and electronic waste recycling. The method comprises the following steps: uniformly mixing a transition metal porphyrin polymer, an aqueous solution of ammonium salt and hydrogen peroxide to obtain a mixed solution; the transition metal porphyrin polymer is obtained by using N'N-dimethylformamide as a solvent, adding 5, 10, 15, 20-tetra (4-carboxyphenyl) porphyrin, a transition metal source and glacial acetic acid, and performing hydrothermal reaction; and the copper-containing electronic waste is added into the mixed solution, and the copper in the electronic waste is dissolved under the action of visible light at 20 DEG C to 40 DEG C and under normal pressure. The application realizes high selectivity and high efficiency of the copper in the electronic waste in the aqueous phase system with the aid of visible light, and lays a foundation for the technical application of photocatalytic recovery of the copper in the electronic waste.

Description

A method for photocatalytic dissolution of copper in electronic waste Technical Field

[0001] This invention relates to the fields of photocatalysis and electronic waste recycling, and more specifically to a method for photocatalytically dissolving copper in electronic waste. Background Technology

[0002] Copper, with its high electrical and thermal conductivity and ductility, is a primary metal required for the development of industries such as electric vehicles, artificial intelligence devices, and power grids. However, due to declining copper ore grades and geopolitical uncertainties, traditional copper mining methods can no longer meet the growing demand for copper. Traditional copper smelting methods include pyrometallurgical and hydrometallurgical processes, but both have different drawbacks: pyrometallurgical processes are energy-intensive, heavily polluting, and only effective for high-grade sulfide ores. While hydrometallurgical processes can extract copper from low-grade ores, they often suffer from equipment corrosion, high wastewater treatment costs, and low extraction efficiency for high-sulfur complex ores. Electrolytic copper smelting can extract high-purity copper, but it suffers from high costs, anode passivation, and impurity accumulation. Electronic waste, such as printed circuit boards and other electronic products, has an average copper content of up to 23.37%, representing a potential copper extraction resource.

[0003] Currently, methods for extracting copper from electronic waste include physical, mechanical, chemical, pyrometallurgical, hydrometallurgical, biological, microwave, and supercritical extraction methods. These methods all face challenges such as poor selectivity, complex procedures, demanding extraction conditions, high costs, limited applicability, and severe environmental pollution. Photocatalysis, by optimizing catalyst performance, generates oxidizing free radicals in the electronic waste extraction system, achieving effective oxidative dissolution of copper. Compared to traditional methods, this process avoids high-temperature and high-pressure operations, consumes less energy, and effectively reduces environmental pollution. A key aspect of photocatalytic copper dissolution technology in electronic waste is achieving efficient oxidative dissolution of copper in green solvents. Currently, most photocatalytic metal dissolution processes are carried out in organic solvents such as acetonitrile, dichloromethane, or mixtures of acetonitrile and water. These solvents, being mostly organic, are highly volatile during photocatalytic dissolution, easily evaporating as the system temperature rises, causing solution loss and affecting copper dissolution efficiency and operator health. Summary of the Invention

[0004] To address the above problems, this invention provides a method for photocatalytically dissolving copper in electronic waste. In an aqueous solution of ammonium salt, visible light is used to achieve highly selective and efficient dissolution of copper in electronic waste, laying the foundation for the application of photocatalytic recycling of copper from electronic waste.

[0005] The purpose of this invention is to provide a method for photocatalytically dissolving copper in electronic waste, comprising the following steps:

[0006] A mixed solution was obtained by uniformly mixing a transition metal porphyrin polymer, an aqueous solution of an ammonium salt, and hydrogen peroxide. The transition metal porphyrin polymer was obtained by hydrothermal reaction at 130℃~150℃ with N'N-dimethylformamide as a solution, 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, a transition metal source, and glacial acetic acid.

[0007] Copper-containing electronic waste is added to a mixed solution. Under the action of visible light at room temperature and pressure, a transition metal porphyrin polymer acts as a catalyst, and copper and ammonium salts coordinate to dissolve the copper in the electronic waste at 20℃~40℃ and normal pressure.

[0008] In a preferred embodiment of the present invention, the ammonium salt is ammonium chloride or ammonium phosphate. Preferably, the present invention uses ammonium chloride.

[0009] In a preferred embodiment of the present invention, the transition metal porphyrin polymer is a transition metal carboxyl porphyrin polymer (manganese carboxyl porphyrin polymer, zinc carboxyl porphyrin polymer, iron carboxyl porphyrin polymer, cobalt carboxyl porphyrin polymer, nickel carboxyl porphyrin polymer) or a transition metal pyridyl porphyrin polymer (cobalt pyridyl porphyrin polymer); the transition metal is manganese, zinc, iron, cobalt, or nickel; further, the transition metal porphyrin polymer is a transition metal carboxyl porphyrin polymer, and even further, the transition metal porphyrin polymer is a manganese carboxyl porphyrin polymer.

[0010] Preferably, manganese is selected for use in this invention.

[0011] In a preferred embodiment of the present invention, the mass ratio of the transition metal porphyrin polymer to copper-containing electronic waste is 20 mg: 0.25 g to 1 g.

[0012] In a preferred embodiment of the present invention, the total volume of copper-containing electronic waste, ammonium salt aqueous solution, and hydrogen peroxide is 1g: 50mL~200mL, and the concentration of the ammonium salt aqueous solution is 0.1 mol / L. It should be noted that, considering evaporation loss after light exposure, an additional 1mL~2mL of water is added based on the calculated solution volume. Taking the present invention as an example, the total volume of ammonium salt aqueous solution and hydrogen peroxide is 50mL. Considering the evaporation loss, the total volume of ammonium salt aqueous solution and hydrogen peroxide is controlled at 52mL.

[0013] In a preferred embodiment of the present invention, the hydrogen peroxide concentration in the aqueous solution of the ammonium salt is 5% to 15%. It should be noted that this concentration refers to the total concentration of hydrogen peroxide in the solution being 5% to 15%. For example, if the experiment uses hydrogen peroxide with a concentration of 30%, it will be diluted to a final concentration of 5% or 15%.

[0014] In a preferred embodiment of the present invention, the dissolution temperature is 35°C to 40°C.

[0015] In a preferred embodiment of the present invention, the dissolution time is 12h to 24h.

[0016] In a preferred embodiment of the present invention, the hydrothermal reaction time of the transition metal porphyrin polymer is 20h~24h.

[0017] In a preferred embodiment of the present invention, the copper-containing electronic waste is a copper-containing printed circuit board or copper-clad laminate.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] Transition metal porphyrin polymers possess excellent light-absorbing units and porous structures. Under visible light irradiation, they enhance the coordination of copper through the nitrogen in the porphyrin ring center and rely on the oxygen anions generated by their excellent light-harvesting properties and more catalytically active sites to achieve efficient photocatalytic dissolution of copper in electronic waste in an aqueous phase system at room temperature and pressure.

[0020] Under visible light irradiation, transition metalloporphyrin polymers generate photogenerated electrons and holes. The photogenerated electrons react with hydrogen peroxide to produce superoxide anion radicals (·O₂⁻), which oxidize copper in electronic waste to Cu. 2+ The ammonium salt in the solution dissociates into NH4. + and the corresponding anion, NH4 + and the corresponding anions react with Cu 2+ Complex ions are formed; for example, ammonium chloride forms the complex ion [CuCl4]. 2- The copper complex ion is oxidized to CuO and Cu(OH)2 under the action of hydrogen peroxide and holes, and then converted into Cu in the solution under acidic conditions. 2+ By leveraging the coordination between copper and ammonium salts, highly selective dissolution of copper ions is achieved. Simultaneously, efficient oxidative dissolution of copper is realized through the oxidation of superoxide anion free radicals and holes generated during the photocatalytic process.

[0021] This invention is carried out in a pure aqueous phase system with water as the solvent, which is significantly different from the strong acids used in traditional hydrometallurgical processes. In particular, this invention has significant green and environmentally friendly characteristics in terms of equipment corrosion and environmental pollution.

[0022] This invention is an oxidation and dissolution of copper under visible light irradiation at room temperature and pressure, which will greatly improve the utilization efficiency and cost of sunlight in subsequent applications. This invention converts copper in electronic waste into free copper ions, rather than complex copper complexes, which facilitates simple reduction and recovery of high-purity copper. Attached Figure Description

[0023] Figure 1 shows the dissolution efficiency of manganese carboxyporphyrin polymer on copper in waste printed circuit boards under different systems. Inset a is a state diagram of the manganese carboxyporphyrin polymer immediately after its addition in Example 1, and inset b is a state diagram of the manganese carboxyporphyrin polymer after the photocatalytic reaction in Example 1 is completed.

[0024] Figure 2 shows the dissolution efficiency of manganese carboxyporphyrin polymer on copper in waste printed circuit boards at different temperatures.

[0025] Figure 3 shows the dissolution efficiency of manganese carboxyporphyrin polymer on copper in waste printed circuit boards under different inorganic salts.

[0026] Figure 4 shows the dissolution efficiency of manganese carboxyporphyrin polymer on copper in waste printed circuit boards at different hydrogen peroxide concentrations.

[0027] Figure 5 shows the dissolution efficiency of manganese carboxyporphyrin polymer on copper in waste printed circuit boards at different solid-liquid ratios.

[0028] Figure 6 shows the dissolution efficiency of cobalt pyridyl porphyrin polymer on copper in waste printed circuit boards at different solid-liquid ratios.

[0029] Figure 7 shows the proportion of copper and other metals in dissolved electronic waste containing manganese carboxyporphyrin.

[0030] Figure 8 shows the dissolution efficiency of copper in photocatalytic printed circuit boards with different metal carboxyl porphyrin polymers.

[0031] Figure 9 shows the solution color before and after the photocatalytic dissolution of copper in the printed circuit board by manganese carboxyporphyrin polymer. In the figure, a is the solution color immediately after the addition of manganese carboxyporphyrin polymer; b is the solution color after 12 hours of photocatalysis by manganese carboxyporphyrin polymer.

[0032] Figure 10 shows the stability of the manganese carboxyporphyrin polymer (35℃), where (a) is the photocatalytic copper dissolution efficiency of the manganese carboxyporphyrin polymer after 5 repeated uses; and (b) is the infrared spectrum of the manganese carboxyporphyrin polymer before and after the photocatalytic reaction. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The transition metal carboxyporphyrin polymer catalyst and the cobalt pyridyl porphyrin polymer preparation method used in this invention are as follows: This invention improves the solubility of carboxyporphyrin in N,N-dimethylformamide solution by sonicating it; at the same time, glacial acetic acid is used to increase the solubility of metal salt in the preparation solution and enhance the reactivity of free carboxyporphyrin with metal salt to obtain metal carboxyporphyrin polymer.

[0035] (1) The preparation process of the manganese carboxyporphyrin polymer catalyst is as follows:

[0036] Accurately weigh (0.1 mmol, 0.0791 g) of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), sonicate at room temperature for 10 minutes, then add 0.245 g of manganese acetate tetrahydrate Mn(CH3COO)2·4H2O, then add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 minutes. After that, transfer the whole thing into the polytetrafluoroethylene liner of the high-pressure reactor and quickly transfer it into the high-pressure reactor and seal it, and heat it at 130℃ for 24 hours. After the reaction was completed and cooled to room temperature, the solution was transferred to centrifuge tubes and centrifuged at 8000 r / min. The centrifuged solid was first washed three times with 5-10 mL of DMF at 8000 r / min for 3 minutes each time, and the supernatant was aspirated with a disposable dropper. The solid was then washed three times with 5-10 mL of deionized water at 8000 r / min for 3 minutes each time. Finally, the centrifuged solid was washed three times with 5-10 mL of anhydrous ethanol at 8000 r / min for 3 minutes each time until the filtrate was clear and transparent. After washing, the centrifuged solid was transferred to a clean petri dish and placed in a vacuum drying oven at 70℃ for 12 hours to obtain the manganese carboxylated porphyrin polymer (MnTCPPploy).

[0037] (2) The preparation process of zinc carboxyporphyrin polymer is as follows:

[0038] Accurately weigh (0.1 mmol, 0.0791 g) of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), sonicate at room temperature for 10 minutes, then add 0.2195 g of zinc acetate dihydrate Zn(CH3COO)2·2H2O, then add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 minutes. After that, transfer the whole mixture into the polytetrafluoroethylene liner of the high-pressure reactor and quickly transfer it into the high-pressure reactor and seal it. Heat at 130℃ for 24 hours. After the reaction was completed and cooled to room temperature, the solution was transferred to centrifuge tubes and centrifuged at 8000 r / min. The centrifuged solid was first washed three times with 5-10 mL of DMF at 8000 r / min for 3 minutes each time, and the supernatant was aspirated with a disposable dropper. The solid was then washed three times with 5-10 mL of deionized water at 8000 r / min for 3 minutes each time. Finally, the centrifuged solid was washed three times with 5-10 mL of anhydrous ethanol at 8000 r / min for 3 minutes each time until the filtrate was clear and transparent. After washing, the centrifuged solid was transferred to a clean petri dish and placed in a vacuum drying oven at 70℃ for 12 hours to obtain zinc carboxyporphyrin polymer (Zn TCPPploy).

[0039] (3) The preparation process of the iron carboxyl porphyrin polymer is as follows:

[0040] Accurately weigh (0.1 mmol, 0.0791 g) of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), sonicate at room temperature for 10 minutes, then add 0.1988 g of ferrous chloride tetrahydrate FeCl2·4H2O, then add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 minutes. After that, transfer the entire mixture into the polytetrafluoroethylene liner of a high-pressure reactor, quickly transfer it into the high-pressure reactor, seal it, and heat it at 130℃ for 24 hours. After the reaction was completed and cooled to room temperature, the solution was transferred to centrifuge tubes and centrifuged at 8000 r / min. The centrifuged solid was first washed three times with 5-10 mL of DMF at 8000 r / min for 3 minutes each time, and the supernatant was aspirated with a disposable dropper. The solid was then washed three times with 5-10 mL of deionized water at 8000 r / min for 3 minutes each time. Finally, the centrifuged solid was washed three times with 5-10 mL of anhydrous ethanol at 8000 r / min for 3 minutes each time until the filtrate was clear and transparent. After washing, the centrifuged solid was transferred to a clean petri dish and placed in a vacuum drying oven at 70℃ for 12 hours to obtain the iron carboxyl porphyrin polymer (FeTCPP polymer).

[0041] (4) The preparation process of cobalt carboxyporphyrin polymer is as follows:

[0042] Accurately weigh (0.1 mmol, 0.0791 g) of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), sonicate at room temperature for 10 minutes, then add 0.249 g of cobalt acetate tetrahydrate Co(CH3COO)2·4H2O, then add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 minutes. Afterwards, transfer the entire mixture into the polytetrafluoroethylene liner of a high-pressure reactor, quickly transfer it into the high-pressure reactor, seal it, and heat it at 130℃ for 24 hours. After the reaction was completed and cooled to room temperature, the solution was transferred to centrifuge tubes and centrifuged at 8000 r / min. The centrifuged solid was first washed three times with 5-10 mL of DMF at 8000 r / min for 3 minutes each time, and the supernatant was aspirated with a disposable dropper. The solid was then washed three times with 5-10 mL of deionized water at 8000 r / min for 3 minutes each time. Finally, the centrifuged solid was washed three times with 5-10 mL of anhydrous ethanol at 8000 r / min for 3 minutes each time until the filtrate was clear and transparent. After washing, the centrifuged solid was transferred to a clean petri dish and placed in a vacuum drying oven at 70℃ for 12 hours to obtain the cobalt carboxyporphyrin polymer (CoTCPPploy).

[0043] (5) The preparation process of nickel carboxyporphyrin polymer is as follows:

[0044] Accurately weigh (0.1 mmol, 0.0791 g) of 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), sonicate at room temperature for 10 minutes, then add 0.237.69 g of nickel chloride hexahydrate NiCl2·6H2O, then add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 minutes. After that, transfer the entire mixture into the polytetrafluoroethylene liner of a high-pressure reactor, quickly transfer it into the high-pressure reactor, seal it, and heat it at 130℃ for 24 hours. After the reaction was completed and cooled to room temperature, the solution was transferred to centrifuge tubes and centrifuged at 8000 r / min. The centrifuged solid was first washed three times with 5-10 mL of DMF at 8000 r / min for 3 minutes each time, and the supernatant was aspirated with a disposable dropper. The solid was then washed three times with 5-10 mL of deionized water at 8000 r / min for 3 minutes each time. Finally, the centrifuged solid was washed three times with 5-10 mL of anhydrous ethanol at 8000 r / min for 3 minutes each time until the filtrate was clear and transparent. After washing, the centrifuged solid was transferred to a clean petri dish and placed in a vacuum drying oven at 70℃ for 12 hours to obtain the nickel carboxyporphyrin polymer (NiTCPP polymer).

[0045] (0) The preparation process of cobalt pyridyl porphyrin polymer is as follows:

[0046] Accurately weigh 0.0619 g (0.1 mmol) of 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), sonicate at room temperature for 10 minutes, then add 0.249 g (1 mmol) of cobalt acetate tetrahydrate, sonicate at room temperature for 10 minutes, transfer the entire mixture into a 20 mL polytetrafluoroethylene liner and quickly transfer it to a high-pressure reactor and seal it. Heat at 150 °C for 18 hours. After the reaction was completed, the high-pressure reactor was cooled to room temperature. The solution was then transferred to centrifuge tubes and centrifuged at 8000 rpm. The centrifuged solid was washed three times with 5-10 mL of DMF (8000 rpm; 3 minutes per wash), followed by three washes with deionized water and anhydrous ethanol (repeated) until the filtrate was clear. After washing, the centrifuged solid was transferred to a clean glass petri dish and dried in a vacuum oven at 70 ℃ for 12 hours to obtain the cobalt pyridyl porphyrin polymer (Co TPyPploy).

[0047] Unless otherwise specified, the transition metal carboxyl porphyrin polymers and cobalt pyridyl porphyrin polymers used in Examples 1 to 16 and Comparative Examples 1 to 6 of this invention were prepared according to the above preparation steps.

[0048] Example 1

[0049] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyporphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After the reaction was terminated, the unreacted printed circuit board was removed, and the final solution was collected.

[0050] Comparative Example 1

[0051] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 26 mL of an aqueous solution containing 0.2675 g of NH4Cl was added sequentially, followed by 26 mL of a 30% hydrogen peroxide solution. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0052] Comparative Example 2

[0053] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of distilled water, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0054] Comparative Example 3

[0055] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 26 mL of distilled water and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0056] Example 2

[0057] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 20 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0058] Example 3

[0059] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 25 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0060] Example 4

[0061] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 30 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0062] Example 5

[0063] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 40 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0064] Example 6

[0065] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyporphyrin polymer (Mn TCPPploy), 26 mL of aqueous solution containing 0.7455 g of (NH4)3PO4, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After the reaction was terminated, the unreacted printed circuit board was removed, and the final solution was collected.

[0066] Comparative Example 4

[0067] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2922 g NaCl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0068] Example 7

[0069] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyporphyrin polymer (MnTCPPploy), 43.33 mL of aqueous solution containing 0.2675 g of NH4Cl, and 8.67 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0070] Example 8

[0071] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 34.7 mL of aqueous solution containing 0.2675 g of NH4Cl, and 17.3 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0072] Comparative Example 5

[0073] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy) and 52 mL of aqueous solution containing 0.2675 g of NH4Cl were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After the reaction was terminated, the unreacted printed circuit board was removed, and the final solution was collected.

[0074] Example 9

[0075] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 0.500 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0076] Example 10

[0077] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 0.250 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0078] Example 11

[0079] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of cobalt pyridyl porphyrin polymer (CoTPyP polymer), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After the reaction was terminated, the unreacted printed circuit board was removed, and the final solution was collected.

[0080] Example 12

[0081] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 0.500 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of cobalt pyridyl porphyrin polymer (Co TPyPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0082] Example 13

[0083] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 0.250 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of cobalt pyridyl porphyrin polymer (Co TPyPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0084] Example 14

[0085] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of zinc carboxyporphyrin polymer (Zn TCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0086] Example 15

[0087] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of iron carboxyl porphyrin polymer (FeTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0088] Example 16

[0089] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of nickel carboxyporphyrin polymer (NiTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After the reaction was terminated, the unreacted printed circuit board was removed, and the final solution was collected.

[0090] Comparative Example 6

[0091] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0092] Example 17

[0093] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (MnTCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant-temperature circulating water system, and the reaction was carried out at 800 rpm for 24 h. After terminating the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0094] The preparation method of the manganese carboxyporphyrin polymer used in this embodiment is as follows: accurately weigh (0.1 mmol, 0.0791 g) of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), sonicate at room temperature for 10 minutes, then add 0.245 g of manganese acetate tetrahydrate Mn(CH3COO)2·4H2O, then add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 minutes. After that, transfer the whole thing into the polytetrafluoroethylene liner of the high-pressure reactor and then quickly transfer it into the high-pressure reactor and seal it, and heat it at 140℃ for 22 hours. After the reaction was completed and cooled to room temperature, the solution was transferred to centrifuge tubes and centrifuged at 8000 r / min. The centrifuged solid was first washed three times with 5-10 mL of DMF at 8000 r / min for 3 minutes each time, and the supernatant was aspirated with a disposable dropper. The solid was then washed three times with 5-10 mL of deionized water at 8000 r / min for 3 minutes each time. Finally, the centrifuged solid was washed three times with 5-10 mL of anhydrous ethanol at 8000 r / min for 3 minutes each time until the filtrate was clear and transparent. After washing, the centrifuged solid was transferred to a clean petri dish and placed in a vacuum drying oven at 70℃ for 12 hours to obtain the manganese carboxyporphyrin polymer (MnTCPP polymer).

[0095] Example 18

[0096] Copper-containing waste printed circuit boards were cut into 1.0 cm × 1.0 cm sheet samples (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxylated porphyrin polymer (Mn TCPPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added sequentially. The temperature of the entire system was maintained at 35 ± 0.5 ℃ using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 20 h. After the reaction was terminated, the unreacted printed circuit board was removed, and the final solution was collected.

[0097] The preparation method of the manganese carboxyporphyrin polymer used in this embodiment is as follows: accurately weigh (0.1 mmol, 0.0791 g) of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF) according to the dissolution, sonicate at room temperature for 10 minutes, then add 0.245 g of manganese acetate tetrahydrate Mn(CH3COO)2·4H2O, then add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 minutes. After that, transfer the whole thing into the polytetrafluoroethylene liner of the high-pressure reactor and then quickly transfer it into the high-pressure reactor and seal it, and heat it at 150°C for 20 hours. After the reaction was completed and cooled to room temperature, the solution was transferred to centrifuge tubes and centrifuged at 8000 r / min. The centrifuged solid was first washed three times with 5-10 mL of DMF at 8000 r / min for 3 minutes each time, and the supernatant was aspirated with a disposable dropper. The solid was then washed three times with 5-10 mL of deionized water at 8000 r / min for 3 minutes each time. Finally, the centrifuged solid was washed three times with 5-10 mL of anhydrous ethanol at 8000 r / min for 3 minutes each time until the filtrate was clear and transparent. After washing, the centrifuged solid was transferred to a clean petri dish and placed in a vacuum drying oven at 70℃ for 12 hours to obtain the manganese carboxyporphyrin polymer (MnTCPP polymer).

[0098] Add 2 mol / L HCl to the final reaction solution, filter through a 0.22 μm filter membrane, and determine the copper content using atomic absorption spectroscopy. Simultaneously, dissolve a 1.0 cm × 1.0 cm slice of the unreacted original printed circuit board using 2.0 mol / L HCl, and determine the total copper content using the same method. Calculate the dissolution efficiency using the formula below. Each experiment was repeated three times, and the average value was taken to ensure data reliability.

[0099]

[0100] E Cu Photocatalytic copper solubility (%), C a C0 represents the Cu content in the solution (mg / L), and C0 represents the total Cu content in the waste copper-clad laminate material (mg / L).

[0101] (1) Effect of catalyst on the dissolution of copper in aqueous system at room temperature

[0102] Figure 1 shows the photocatalytic dissolution of copper in printed circuit boards in Examples 1 and Comparative Examples 1-3 with and without a catalyst. The influence of the presence or absence of coordinating ions on copper recovery in the aqueous system is also compared. The results indicate that the photocatalyst and coordinating ions are crucial for copper dissolution and recovery. When a metal carboxyporphyrin polymer (MnTCPP polymer) is introduced as a photocatalyst, the copper dissolution rate is significantly improved. Control experiments show that the dissolution rate increases to 74.71% after the synergistic introduction of the photocatalyst and NH4Cl, which is approximately 73% higher than the single oxidant system. Compared with the copper dissolution rate in pure water, the addition of the catalyst and coordinating ions improves the copper recovery rate, demonstrating the research significance of this system for copper recovery.

[0103] (2) Effect of temperature on photocatalytic dissolution of copper

[0104] In Examples 1-5, with a catalyst concentration of 20 mg, an ammonium salt aqueous solution concentration of 0.1 mol / L, and a total volume ratio of copper-containing electronic waste to the ammonium salt aqueous solution and hydrogen peroxide of 1 g: 50 mL, and with hydrogen peroxide at a mass concentration of 15% in the ammonium salt aqueous solution, the effect of temperature on copper dissolution was investigated. As shown in Figure 2, temperature significantly affects the photocatalytic dissolution reaction. Between 20°C and 40°C, the dissolution efficiency of copper in the electronic waste sample using the metal carboxyporphyrin polymer (MnTCPP polymer) as a photocatalyst continuously increases with increasing temperature, demonstrating that increasing temperature promotes the entire reaction. The optimal solubility of 95.48% was achieved at 40°C. Based on temperature control requirements, this invention subsequently selected 35°C for further processing.

[0105] (3) Effect of inorganic salts on photocatalytic copper dissolution

[0106] The dissolution efficiency of copper is highly correlated with the inorganic salts in the photocatalytic system. Ions with strong coordination interactions with copper ions were selected and combined to prepare different inorganic salt solutions. In Comparative Example 4, Example 4, and Example 6, the catalyst addition was kept at 20 mg, the concentration of the ammonium salt aqueous solution was 0.1 mol / L, the ratio of copper-containing electronic waste to the total volume of the ammonium salt aqueous solution and hydrogen peroxide was 1 g: 50 mL, and the mass concentration of hydrogen peroxide in the ammonium salt aqueous solution was 15%. The experiment was repeated in different systems of NaCl, NH4Cl, and (NH4)3PO4 at a temperature of 35°C. The results are shown in Figure 3. When NaCl was used, the dissolution of copper was not promoted, and the final dissolution rate was only 1.6%. Comparing the results of NH4Cl and (NH4)3PO4, it can be seen that when NH4Cl is present in the solution... +At these temperatures, the copper dissolution efficiencies were 74.71% and 64.28%, respectively. However, with the synergistic effect of NH₄⁺ and Cl⁻ ions, the copper dissolution rate increased to 74.71% at 35°C. Compared to other halide ammonium salts such as ammonium bromide, the complex ions formed by ammonium chloride and copper are more easily oxidized to CuO and Cu(OH)₂ under the preparation conditions of this invention, while the complex ion [CuBr₄] formed by bromide and copper is... 2- Due to its higher stability, it is difficult to ultimately convert it into Cu. 2+ Cu 2+ It makes it easier to recycle the recovered liquid back into pure copper for later use and recycling.

[0107] (4) Effect of hydrogen peroxide concentration on photocatalytic copper dissolution

[0108] H2O2 can effectively oxidize copper in solid waste, further promoting copper dissolution. In Examples 1, 7-8, and Comparative Example 5, the catalyst dosage was kept at 20 mg, the concentration of the ammonium salt aqueous solution was 0.1 mol / L, and the total volume ratio of copper-containing electronic waste to the ammonium salt aqueous solution and hydrogen peroxide was 1 g: 50 mL. The mass concentration of hydrogen peroxide in the ammonium salt was varied at 35°C. As shown in Figure 4, when the H2O2 concentration was 5%, the copper dissolution rate reached over 95%. With increasing H2O2 concentration, the copper dissolution rate gradually decreased. This indicates that in this reaction, a higher concentration of H2O2 as an oxidant is not necessarily more beneficial. When the H2O2 concentration is too high, the large amount of oxygen bubbles generated by the decomposition of H2O2 adsorbs onto the surface of the printed circuit board, hindering the contact between the copper on the board and the solution, thereby reducing the copper dissolution efficiency.

[0109] (5) Effect of solid-liquid ratio on photocatalytic dissolution of copper

[0110] In Examples 1, 9, and 10, the catalyst dosage was kept at 20 mg, the concentration of the ammonium salt aqueous solution was 0.1 mol / L, the mass concentration of hydrogen peroxide in the ammonium salt aqueous solution was 15%, and the temperature was 35°C. The ratio of the mass of the copper-containing waste printed circuit board sample to the solution volume (solid-liquid ratio) was changed to study the change in copper solubility in the system, as shown in Figure 5. The results show that when the solid-liquid ratio increased from 1 g:50 mL to 1 g:200 mL, the copper solubility increased. When the solid-liquid ratio increased from 1 g:50 mL to 1 g:100 mL, the copper recovery rate increased from 74.71% to 80.98%. When the solid-liquid ratio was 1 g:200 mL, the copper recovery rate further increased to 83.24%. This indicates that as the solid-liquid ratio decreases, the copper solubility increases slightly.

[0111] In Examples 11-13, cobalt-pyridyl porphyrin polymer was used as the catalyst. The catalyst addition was maintained at 20 mg, the concentration of the ammonium salt aqueous solution was 0.1 mol / L, the mass concentration of hydrogen peroxide in the ammonium salt aqueous solution was 15%, and the temperature was 35°C. The ratio of the mass of copper-containing waste printed circuit board samples to the solution volume was varied to study the change in copper dissolution rate in the system, as shown in Figure 6. At a solid-liquid ratio of 1:50, its copper dissolution efficiency was 68.35%, which is lower than that of manganese carboxylated porphyrin polymer at the same solid-liquid ratio. The results show that manganese carboxylated porphyrin polymer plays a crucial role in the photocatalytic dissolution of copper in printed circuit boards. Both the peripheral substituents and the central metal ion of the porphyrin polymer significantly affect the conduction band position of the photocatalyst. The conduction band potential of manganese carboxylated porphyrin polymer is lower, significantly lower than that of O2 / ·O2⁻, making it more likely to generate superoxide anion radicals during photocatalysis, thus resulting in higher photocatalytic activity.

[0112] Figure 7 shows the content of different metals in the original waste printed circuit boards. Examples 1, 11, 14-16, and comparative examples investigated the solubility of copper in different transition metal porphyrin polymers. Figure 8 shows that the manganese carboxylate porphyrin polymer recovered almost all of the copper, with a selectivity of up to 99%. Compared with porphyrin monomers, the manganese carboxylate porphyrin polymer has a specific surface area of ​​43.499 m². 2 / g is a mesoporous material that exposes more active sites during photocatalytic dissolution, thus promoting the photocatalytic reaction to a greater extent. Furthermore, due to the multiple valence changes of Mn, it can better promote the transfer of photocatalytic electrons, which is conducive to the generation of reactive oxygen species. It also has stronger thermal stability and is more stable in water. Moreover, the above photocatalytic process can be excited to generate photogenerated electrons and holes under visible light irradiation, which promotes the oxidation and dissolution of copper.

[0113] Figure 9 shows the solution color before and after using manganese carboxyporphyrin polymer to photocatalyze the dissolution of copper in a printed circuit board in Example 1. In Figure 9a, the dark purple color is the solution color immediately after adding the manganese carboxyporphyrin polymer. In Figure 9b, the blue color is the solution color after 12 hours of photocatalysis by the manganese carboxyporphyrin polymer. The solution turns significantly blue after the photocatalytic reaction, which is the characteristic color of copper ions.

[0114] After five uses following the operating method of Example 1, the catalyst maintained a high dissolution efficiency, as shown in Figure 10(a). The decrease in efficiency was due to catalyst loss from repeated centrifugation. As shown in Figure 10(b), the catalyst surface groups did not change before and after the catalytic dissolution reaction, indicating its high stability.

[0115] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0116] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for photocatalytically dissolving copper in electronic waste, characterized in that, The process includes the following steps: A mixed solution is obtained by uniformly mixing a transition metal porphyrin polymer, an aqueous solution of an ammonium salt, and hydrogen peroxide; the transition metal porphyrin polymer is obtained by hydrothermal reaction at 130℃~150℃ with N'N-dimethylformamide as solvent, 5,10,15,20-tetra(4-carboxyphenyl)porphyrin, a transition metal source, and glacial acetic acid; the ammonium salt is ammonium chloride or ammonium phosphate, and the concentration of the aqueous solution of the ammonium salt is 0.1 mol / L; copper-containing electronic waste is added to the mixed solution, and under visible light, the transition metal porphyrin polymer acts as a photocatalyst, coordinating copper and the ammonium salt, dissolving the copper in the electronic waste under conditions of 20℃~40℃ and normal pressure.

2. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, The transition metal porphyrin polymers are transition metal carboxyl porphyrin polymers or transition metal pyridyl porphyrin polymers, and the transition metals are manganese, zinc, iron, cobalt or nickel.

3. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, The mass ratio of transition metal porphyrin polymer to copper-containing electronic waste is 20 mg: 0.25 g ~ 1 g.

4. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, The total volume of copper-containing electronic waste, ammonium salt aqueous solution, and hydrogen peroxide is 1g: 50mL~200mL.

5. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, The mass concentration of hydrogen peroxide in an aqueous solution of ammonium salt is 5% to 15%.

6. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, The dissolution temperature is 35℃~40℃.

7. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, The dissolution time is 12h~24h.

8. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, The hydrothermal reaction time for the transition metal porphyrin polymer is 20-24 hours.

9. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that, Copper-containing electronic waste refers to copper-containing printed circuit boards or copper-clad laminates.

Images